The invention relates to a substrate processing apparatus that performs given processing such as resist coating and developing on substrates such as semiconductor substrates, glass substrates for liquid crystal displays, glass substrates for photomasks, and substrates for optical disks.
As is generally known, products such as semiconductors and liquid crystal displays are manufactured through a series of processes, such as cleaning, resist coating, exposure, developing, etching, formation of an interlayer insulation film, heat treatment, and dicing, on substrates as described above. U.S. Patent Application Publication No. 2003/0213434 discloses a substrate processing apparatus (what is called a coater-and-developer) that incorporates a plurality of processing units for performing, for example, resist coating, developing, and their accompanying heat treatments, out of the processes described above, and performs a series of photolithographic processes on substrates while transporting the substrates into circulation among those processing units using transport robots.
Such a substrate processing apparatus needs to derive appropriate processing conditions for each processing unit in order to achieve desired results. Even after deriving the processing conditions, the apparatus also needs to check, as necessary, whether the initial setting conditions work properly without causing any processing problem.
Referring to the substrate temperature which is one of the important factors in the processing conditions, Japanese Patent Application Laid-open No. 2004-140167 has suggested a technique for measuring the temperature using damped oscillations caused by the resonance of quartz resonators, mounted on a substrate for temperature measurement, at their characteristic frequencies. Quartz resonators have high heat resistance and high heat sensitivity so that high-precision temperature measurements are possible even with high-temperature substrates.
Such a conventional technique, however, has difficulty in real-time temperature measurement of a substrate being processed, so it was necessary to process substrates in practical use over and over and check the processing results in order to derive appropriate processing conditions. The difficulty in the real-time temperature measurement makes it considerably difficult to detect the occurrence of any processing problem at an early stage.
Use of the temperature-measuring technique disclosed in Japanese Patent Application Laid-open No. 2004-140167 allows a certain degree of real-time temperature measurement of a substrate being processed; however, equipping each processing unit with various mechanisms such as sensor coils that accompany the temperature measurement not only complicates the configuration of each processing unit but also brings about various adverse effects on processes and maintenance.